FIG. 1 illustrates an exemplary probing system 90 for testing electronic devices, which may be, for example, dies (not shown) on a newly manufactured semiconductor wafer 12. The probing system 90 of FIG. 1 includes a test head 4 and a prober 2 (which is shown with a cut-away 26 to provide a partial view of the inside of the prober 2). To test the dies (not shown) of the semiconductor wafer 12, the wafer 12 is placed on a moveable stage 6 as shown in FIG. 1, and the stage 6 is moved such that terminals 22 on dies (not shown) of the wafer 12 are brought into contact with probes 66 of a probe card assembly 20. Temporary electrical connections are thus established between the probes 66 and dies (not shown) of the wafer 12 to be tested.
Typically, a cable 10 or other communication means connects a tester (not shown) with the test head 4. Electrical connectors 14 electrically connect the test head 4 with the probe card assembly 20, and the probe card assembly 20 includes electrical paths (not shown) to the probes 66. The cable 10, test head 4, electrical connectors 14, and probe card assembly 20 (which includes probes 66) thus provide electrical paths between the tester (not shown) and the die terminals 22 of the wafer 12 being tested. Thus, while the probes 66 are in contact with the terminals 22 of the dies (not shown) on the wafer 12, cable 10, test head 4, electrical connectors 14, and probe card assembly 20 provide a plurality of electrical paths between the tester (not shown) and the dies (not shown). The tester (not shown) writes test data through these electrical paths to the dies (not shown), and response data generated by the dies in response to the test data is returned to the tester through these electrical paths.
A typical wafer 12 comprises numerous dies (not shown). Indeed, a wafer 12 may include dozens or even hundreds of dies (not shown). Typically, probe card assembly 20 is not capable of contacting all of the dies (not shown) on a wafer 12. To test all of the dies (not shown) on a wafer 12, the stage 6 moves some of the dies (not shown) of wafer 12 into contact with the probes 66 of the probe card assembly 20, and the tester (not shown) runs tests on those dies (not shown). The stage 6 then moves the wafer 12 such that others of the dies (not shown) contacted the probes 66, and the tester (not shown) runs the same tests on those dies. This process of moving the wafer 12 to bring some of the dies (not shown) into contact with the probes 66 and testing those dies (not shown) continues until all of the dies (not shown) of the wafer 12 are tested.
As probe card assembly technology has advanced, the size of the array of probes 66 has been increased in order to contact more dies (not shown). One strategy for creating large probe arrays 66 involves using multiple probe substrates 66. That is, multiple probe substrates 66, each comprising a plurality of probes, are positioned adjacent one another so that the probes on probe substrates 66 form a large array of probes. U.S. Pat. Nos. 5,806,181, 6,690,185, 6,640,415, and 6,509,751 (each of which is incorporated herein by reference in its entirety) disclose nonlimiting examples of probe card assemblies with multiple probe substrates. The probes 66 and die terminals 22, both of which are typically small, must be precisely aligned, which necessitates precise positioning of the multiple probe substrates. Methods and apparatuses for precisely positioning such probe substrates are needed.